A ring of radius `R` rolls without slipping on a rough horizontal surface with a constant velocity. The radius of curvature of the path followed by any particle of the ring at the highest point of its path will be :
.

Options

A. R
B. 2 R
C. 4 R
D. none of these

Answer

C

Explanation

( c) Radius of Curvature `= (("velocity")^2)/("Normal Acceleration")`
=`((2 v)^2)/(v^2//R) = 4 R`.
.